(i) Technical Field
A certain aspect of the embodiments discussed herein is related to a semiconductor device, especially related to a semiconductor device where a protective film is provided on a semiconductor layer.
(ii) Related Art
A protective film composed of an insulating material such as a silicon nitride (SiN) may be provided on the surface of a semiconductor layer to protect the semiconductor layer of a semiconductor device from stress and fouling. Also, a protective film may be provided to protect the top surface of a semiconductor device in the molding process.
Japanese Laid-Open Patent Publication No. 5-129430 (hereinafter referred to as Document 1) discloses a technique to suppress the exfoliation of a protective film by forming a metallic film at the boundary between the protective film and a scribe line.
However, moisture may penetrate from the boundary between a semiconductor layer and a protective film, and corrode an electrode.
For example, in FIG. 1 of Document 1, if a protective film is a polyimide layer, the exfoliation of the protective film can be suppressed because a metallic film provided at outmost side covers the end portion of the protective film. However, since polyimide has low resistance to moisture penetration, moisture penetrating through the protective film may reach an external lead electrode, and corrode the external lead electrode.